JP2023178608A - Liquid discharge head and manufacturing method for the same - Google Patents

Abstract

To provide a liquid discharge head that can make both effect of inhibiting a passage forming member from peeling from a substrate and a coating property of the passage forming member compatible.SOLUTION: The liquid discharge head comprises a substrate, a passage forming member in which a discharge port for discharging liquid and a passage for supplying liquid to the discharge port are formed, and an energy generating element configured to generate energy for discharging liquid. The substrate has a convex part protruding from the substrate toward the passage forming member, where the convex part has a second layer and a first layer in this order from the substrate side. Cross sectional areas of the second layer are smaller than cross sectional areas of the first layer, in a plane parallel to the substrate. A portion of the passage forming member intrudes into a space surrounded by the first layer of the convex part and the substrate.SELECTED DRAWING: Figure 2

Description

The present invention relates to a liquid ejection head and a method for manufacturing the same.

A liquid ejection head is used in a liquid ejection device such as an inkjet recording device, and includes a flow path forming member and a substrate. The channel forming member provided on the substrate is mainly made of resin or the like, and has a liquid channel, a discharge port, and the like. The substrate is mainly made of silicon or the like, and has a supply port for supplying liquid to the channel, an energy generating element for ejecting the liquid, and the like. The liquid is supplied to the channel from the liquid supply port, is given energy by the energy generating element, is ejected from the ejection port, and lands on a recording medium such as paper.

The flow path forming member needs to have sufficient adhesion to the substrate so that it does not easily peel off from the substrate. However, depending on the type of ink (liquid) ejected by the liquid ejection head, the flow path forming member may peel off from the substrate. For example, when a highly alkaline ink is used, the ink may penetrate into the channel forming member, causing the channel forming member to deform and peel off from the substrate.

As a technique for suppressing separation of a flow path forming member from a substrate, Patent Document 1 discloses a liquid ejection head in which a recessed portion is formed on a surface of a substrate that contacts the flow path forming member. Specifically, it is stated that a part of the channel-forming member formed by applying resin or the like fits into the recess, thereby making it difficult to separate the channel-forming member from the substrate due to the anchor effect. ing.

Japanese Patent Application Publication No. 2015-74118

However, in the liquid ejection head described in Patent Document 1, when applying the resin that is a raw material for the flow path forming member to the substrate, the coating properties on the substrate may deteriorate. For example, if the recesses are made small in order to arrange energy generating elements at a high density, it becomes difficult for the resin to enter the recesses when applying the resin that is the raw material for the channel forming member, and air bubbles may remain in the recesses. There were cases where it was put away. Furthermore, even when the resin used as the raw material for the flow path forming member has a high viscosity, the flow path forming member becomes difficult to enter the recessed portion. In this way, if the resin that is the raw material for the channel forming member has poor applicability to the recess and the channel forming member does not fit into the recess, the bond between the channel forming member and the substrate may be strengthened due to the anchor effect. become unable.

The present invention has been made in view of the above-mentioned problems, and provides a liquid ejection head that can achieve both the effect of suppressing peeling of a flow path forming member from a substrate and the applicability of the flow path forming member. The purpose is to

In order to achieve the above object, a liquid ejection head according to the present invention includes a substrate, a flow path forming member in which an ejection port for ejecting liquid and a flow path for supplying liquid to the ejection port are formed. and an energy generating element configured to generate energy for ejecting liquid, the substrate having a convex portion protruding from the substrate side toward the flow path forming member. , the convex portion has a second layer and a first layer in order from the substrate side, and the cross-sectional area of the second layer in a plane parallel to the substrate is equal to that of the first layer. A part of the flow path forming member is smaller than the cross-sectional area and enters a space surrounded by the first layer of the convex portion and the substrate.

According to the present invention, it is possible to provide a liquid ejection head that can achieve both the effect of suppressing peeling of a flow path forming member from a substrate and the applicability of the flow path forming member.

FIG. 1 is a diagram showing an example of a liquid ejection head of the present invention. FIG. 1 is a diagram showing an example of a liquid ejection head of the present invention. FIG. 1 is a diagram showing an example of a method for manufacturing a liquid ejection head of the present invention. FIG. 3 is a diagram showing an example of the arrangement of convex portions in the liquid ejection head of the present invention. FIG. 3 is a diagram showing an example of the arrangement of convex portions in the liquid ejection head of the present invention. FIG. 1 is a diagram showing an example of a liquid ejection head of the present invention. It is a figure which shows an example of the manufacturing method of the electrode pad in this invention.

EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing this invention is demonstrated. However, the configurations described in the embodiments and examples of the present invention are merely examples, and the scope of the present invention is not intended to be limited thereto.

(First embodiment)
1 and 2 are diagrams showing an example of a liquid ejection head of the present invention. FIG. 1 is a perspective view of the liquid ejection head, and FIG. 2(a) is a sectional view of the liquid ejection head taken along line AA in FIG. The liquid ejection head shown in FIG. 1 includes a substrate 3 and a flow path forming member 6 that forms a liquid flow path 5 on the surface of the substrate 3. Substrate 3 includes a silicon substrate 7 and a silicon oxide film 12 . The substrate 3 has an energy generating element 1 that generates energy for discharging liquid, an electrode pad 8 for supplying electricity to the energy generating element 1, on the front side that is in contact with the flow path forming member 6. It has a protective layer 9 that protects the energy generating element 1 and electrically insulates it from the liquid. The energy generating element 1 is formed of a heater (high resistance material typified by TaSiN or WSiN) or a piezoelectric element, and can be formed with a thickness of 10 to 100 nm. Wiring (not shown) for passing a current through the energy generating element 1 is formed in the energy generating element 1 . The wiring can be formed using, for example, AlCu, AlSi, or AlSiCu, and can have a thickness of about 300 to 1000 nm. A protective layer 9 is formed on the energy generating element 1 and the wiring. The protective layer 9 may be made of silicon nitride, carbon nitride, silicon carbonitride, etc., may be composed of a film of a plurality of materials, and may be formed to have a thickness of about 100 to 500 nm. The channel forming member 6 is made of, for example, resin or an inorganic film, and has a discharge port 4 and a channel 5. A supply port 2 for supplying liquid is formed in the substrate 3 , and the liquid is supplied from the supply port 2 to the channel 5 , is given energy by the energy generating element 1 , and is discharged from the discharge port 4 .

In the liquid ejection head of the present invention, the substrate 3 is formed with a convex portion 20 that protrudes from the substrate side toward the channel forming member 6 . FIG. 2(b) is an enlarged view of the vicinity of the convex portion 20 in FIG. 2(a). As described above, the protective film 9 is formed on the front side of the substrate 3 to protect the energy generating element 1 and electrically insulate it from the liquid. The convex portion 20 is formed on the protective layer 9 and includes at least a first layer 21 and a second layer 22 disposed below the first layer. The first layer 21 and the second layer 22 can each be formed to have a thickness of about 100 to 500 nm. Here, the cross-sectional area of the second layer 22 in a plane parallel to the substrate 3 is smaller than the cross-sectional area of the first layer 21. That is, the convex portion 20 has a portion where the first layer 21 protrudes without overlapping with the second layer 22. Note that the convex portion 20 may include layers other than the first layer and the second layer as long as some of the layers protrude from the lower layer. Further, the shape of the convex portion 20 preferably has rotational symmetry with respect to an axis passing through the center of gravity of the convex portion and parallel to the liquid ejection direction.

If the protrusion amount L of the first layer 21 with respect to the second layer 22 is too large, the first layer 21 will sag in the direction of the substrate 3. Therefore, it is preferable that the protrusion amount L is 0.5 times or more and twice or less the thickness of the first layer 21 in the same direction as the liquid discharge direction. In this case, when the first layer 21, the second layer 22, and the center of gravity of the convex part 20 are projected onto a plane parallel to the substrate 3, the second layer on a straight line passing through the center of gravity of the convex part 20 The length from the outer edge of 22 to the outer edge of the first layer 21 is at least 0.5 times and at most 2 times the thickness of the first layer 21 in the direction orthogonal to the plane parallel to the substrate 3. .

The flow path forming member 6 forms a flow path so as to cover the convex portion 20 . As shown in FIG. 2(b), a portion 6a of the flow path forming member 6 enters the recessed space 20a surrounded by the first layer 21 (convex portion 20) and the protective layer 9 (substrate 3). The anchor effect makes it difficult for the channel forming member 6 to peel off from the substrate 3.

A plurality of convex portions 20 may be formed around the flow path 5. FIG. 4 shows a liquid ejection head in which a convex portion 20 is formed around the flow path 5. As shown in FIG. FIG. 4 is a cross-sectional view at a position within the liquid ejection head corresponding to line BB in FIG. 2(a), and the position of the energy generating element 1 is indicated by a dotted line. Further, it is preferable to form a plurality of small convex portions 20 because the contact area between the flow path forming member 6 and the convex portions 20 becomes large and the adhesion becomes high. FIG. 5 shows an example in which a plurality of convex portions 20 having short lengths in the horizontal direction with respect to the substrate 3 are arranged side by side between the flow channels 5. FIG. 5(a) is a sectional view taken along line BB in the liquid ejection head in FIG. 2(a), and FIG. 5(b) is a sectional view taken along line CC in FIG. 5(a). be. By arranging a plurality of convex portions 20 as shown in FIG. 5, the contact area between the flow path forming member 6 and the convex portions 20 can be increased, and the adhesion is improved.

Next, an example of a method for manufacturing a liquid ejection head of the present invention will be described using FIG. 3.

First, as shown in FIG. 3(a), a substrate 3 having a silicon substrate 7 and a silicon oxide film 12 is prepared. On the front side of the substrate 3, an energy generating element 1 and a protective layer 9 are formed. Further, an anti-cavitation film 10 may be formed on the protective film 9 to protect the energy generating element 1 from cavitation during liquid ejection. As the anti-cavitation film 10, metals such as tantalum (Ta) and iridium (Ir), which have high mechanical stability, can be used.

Next, as shown in FIG. 3(b), a second layer 22 is formed, and a first layer 21 is formed thereon. A known method may be used to form the first film and the second film, and for example, CVD may be used.

As the material for forming the convex portion 20, it is preferable to select a material that has good wettability with the channel forming member 6. For example, in the channel forming member 6 made of resin, the first layer 21 and the second layer 22 can be formed of a film containing Si and at least one of C, N, and O. Further, the combination of materials for the first layer 21 and the second layer 22 is selected so that the etching rates are different during isotropic etching (wet etching) described later. For example, SiOCN can be used as the first layer 21. Here, SiOCN is represented by the following general formula (1)
Si _w O _x C _y N _z (w+x+y+z=100, 37≦w≦60, 30≦x≦53, 6≦y≦29, 4≦z≦9)...(1)
It is a material expressed by . In this case, as the second layer 22, SiO or SiO ₂ can be used. These materials are preferable because they have good wettability and adhesion with the flow path forming member 6 made of resin.

Next, as shown in FIG. 3(c), a resist is applied on the second layer 22 and the first layer 21. Subsequently, by exposing and developing, a pattern 30 for forming a desired convex shape is formed as shown in FIG. 3(d).

Thereafter, as shown in FIG. 3(e), the first layer 21 is patterned by anisotropic etching. Here, dry etching can be used as the anisotropic etching. At this time, it is desirable to over-etch so that the second layer 22 remains.

Subsequently, as shown in FIG. 3(f), the second layer 21 is patterned by isotropic etching. Here, in the isotropic etching, a wet etching solution is used that isotropically etches the second layer 22 more selectively than the first layer 21. For example, as described above, when the first layer 21 is SiOCN and the second layer 22 is SiO or _SiO2 , buffered hydrofluoric acid (BHF) can be used as the wet etching solution. The first layer 21 made of SiOCN has higher resistance to BHF than the second layer 22 made of SiO or _SiO2 , so the second layer 22 is selectively etched. At this time, the second layer 22 is side-etched under the first layer 21, and the cross-sectional area of the second layer 22 in the direction parallel to the substrate 3 is the same as that of the first layer 21 in the direction parallel to the substrate 3. smaller than the cross-sectional area. Thereby, the convex portion 20 having an eave shape can be formed. At this time, if excessive side etching is performed, the first layer 21 will hang down toward the substrate 3, so the side etching amount (L) of the second layer 22 is set to a value relative to the thickness of the first layer 21. Therefore, it is preferable to set it to 0.5 times or more and 2 times or less. For example, when the thickness of the first layer 21 is 150 nm, the side etching amount is preferably 75 nm or more and 300 nm or less. Furthermore, when the second layer 22 is isotropically etched, if the second layer 22 is left as described above and the anti-cavitation film 10 has high resistance to the wet etching solution, the anti-cavitation film 10 can be etched in excess. It will not be over-etched. For example, Ta is preferable as a material for the anti-cavitation film 10 because it has excellent resistance to BHF.

Next, as shown in FIG. 3(g), by removing the resist, the convex portions 20 can be formed by one-time resist application and exposure.

Subsequently, the channel forming member 6 is formed on the substrate 3 on which the convex portion 20 is formed so as to cover the convex portion 20 . The flow path forming member 6 may be formed by an existing method, such as the method disclosed in Patent Document JP-A-2015-74118. For example, by using a material with fluidity as the flow path forming member 6, a portion 6a of the flow path forming member can enter the space 20a in the convex portion 20. Since the flow path forming member can enter the space 20a along the substrate 3, there is less concern that bubbles will get mixed in compared to the liquid ejection head described in Prior Document 1 in which a recess is provided in the substrate. The invention has excellent applicability of the flow path forming member 6.

(Second embodiment)
Descriptions of parts common to the first embodiment will be omitted.

FIG. 6 shows a liquid ejection head in a second embodiment. As shown in FIG. 6, a third layer 23 may be formed between the second layer 22 and the substrate 3. The cross-sectional area of the third layer 23 in a plane parallel to the substrate 3 is larger than the cross-sectional area of the second layer 22. Thereby, when the liquid ejection head does not have the anti-cavitation film 10, the third layer 23 can be used as an etching stop layer when performing isotropic etching in the step of forming the convex portions 20. The third layer 23 is preferably made of a material that is not etched during isotropic etching of the second layer, and the same material as the first layer 21 can be used. For example, the aforementioned SiOCN can be used.

(Third embodiment)
Descriptions of parts common to the first embodiment will be omitted.

The convex portion 20 may be formed simultaneously with the electrode pad 8. FIG. 7 shows a process for forming the electrode pad 8, which is similar to the process for forming the convex portions shown in FIGS. 3(c) to 3(g). Here, the first layer 21 and the second layer 22 in FIG. 7(f) can be an insulating film near the electrode pad, which is preferable because the manufacturing process is simplified. An example of a method for simultaneously forming the convex portion 20 and the electrode pad 8 will be described below with reference to FIGS. 2 and 7.

First, a substrate 3 having a protective film 9 formed on its surface side is prepared. Subsequently, prior to forming the convex portions 20, an anti-cavitation film 10 is formed on the protective film 9. At this time, at the electrode pad forming position, the electrode pad 8 is simultaneously formed using the material of the anti-cavitation film 10 (FIGS. 2(a) and 7(a)). Note that instead of the anti-cavitation film 10, the third layer 23 may be formed simultaneously with the electrode pad 8.

Next, as shown in FIG. 3(b) and FIG. 7(b), a first layer 21 and a second layer 22 are formed.

Next, as shown in FIGS. 3(c) and 7(c), a resist is applied on the first layer 21. Subsequently, the resist is exposed and developed to form a pattern 30 for forming protrusions and electrode pads, as shown in FIGS. 3(d) and 7(d). Next, as shown in FIGS. 3(e) and 7(e), the first layer 21 is anisotropically etched, and the second layer 21 is etched as shown in FIGS. 3(f) and 7(f). The protrusions 20 are formed by isotropically etching the layer 22. As a result, the anti-cavitation film 10 is exposed to the surface at the electrode pad formation position. Next, as shown in FIGS. 3(g) and 7(g), by removing the resist, the convex portion 20 and the electrode pad 8 can be formed at the same time by applying the resist and exposing it once.

In this embodiment, the anti-cavitation film 10 or the third layer 23 formed at the same time as the electrode pad 8 is preferably formed of Ir, and the outermost layer in contact with the channel forming member 6 has a multilayer structure of Ir. There may be. Ir is preferable for the electrode pad 8 because its surface is not easily oxidized and it is easy to make contact with a needle during electrical testing.

Hereinafter, the present invention will be explained in more detail using Examples.

A liquid ejection head having the configuration shown in FIG. 2 was formed. First, as shown in FIG. 3(a), a substrate 3 having a silicon substrate 7 and a silicon oxide film 12 was prepared. On the surface side of the substrate 3, an energy generating element 1, wiring (not shown) for passing a current through the energy generating element 1, a protective film 9, and an anti-cavitation film 10 are formed. The energy generating element 1 was formed of TaSiN with a thickness of about 10 to 15 nm. Further, the wiring was formed of AlCu containing about 0.5% Cu and having a thickness of about 600 nm. A protective layer 9 of SiN with a thickness of 300 nm was formed thereon, and an anti-cavitation film 10 of Ta with a thickness of 230 nm was formed on the protective layer 9.

Next, as shown in FIG. 3B, a 100 nm thick SiO film was formed as the second layer 21, and a 150 nm thick SiOCN film was formed as the first layer 21 thereon.

Next, as shown in FIGS. 3(c) and 3(d), a resist is applied on the second layer 22 and the first layer 21, and a pattern for forming convex portions is formed by exposure and development. 30 was formed.

Subsequently, as shown in FIGS. 3(e) to 3(g), the first layer 21 was patterned by dry etching, and the second layer 22 was patterned by wet etching to form convex portions 20. Note that BHF was used as the wet etching solution.

Thereafter, the flow path forming member 6 is formed on the substrate 3 so that a portion 6a of the flow path forming member 6 enters the space of the recess surrounded by the first layer 21 (convex portion 20) and the substrate 3. , a liquid ejection head shown in FIG. 2 was formed. In the obtained liquid ejection head, no separation of the flow path forming member 6 from the substrate 3 was observed.

1 Energy generating element 2 Supply port 3 Substrate 4 Discharge port 5 Channel 6 Channel forming member 7 Silicon substrate 8 Electrode pad 9 Protective layer 10 Anti-cavitation film 12 Silicon oxide film 20 Convex portion 21 First layer 22 Second layer 23 Third layer 30 Pattern

Claims (10)

A substrate, a flow path forming member in which an ejection port for ejecting liquid and a flow path for supplying liquid to the ejection port are formed, and an energy generating element configured to generate energy for ejecting the liquid. A liquid ejection head having:
The substrate has a convex portion protruding from the substrate side toward the flow path forming member,
The convex portion includes a second layer and a first layer in order from the substrate side,
The cross-sectional area of the second layer in a plane parallel to the substrate is smaller than the cross-sectional area of the first layer,
A liquid ejection head characterized in that a part of the flow path forming member enters a space surrounded by the first layer of the convex portion and the substrate. The first layer is made of a material represented by the following general formula (1) Si _w O _x C _y N _z (w+x+y+z=100, 37≦w≦60, 30≦x≦53, 6≦y≦29, 4≦ z≦9)...(1)
has
The liquid ejection head according to claim 1, wherein the second layer includes SiO or _SiO2 . Regarding the convex portion, when the first layer, the second layer, and the center of gravity of the convex portion are projected onto a plane parallel to the substrate, on a straight line passing through the center of gravity of the convex portion, The length from the outer edge of the second layer to the outer edge of the first layer is at least 0.5 times and at most 2 times the thickness of the first layer in the direction orthogonal to the plane. The liquid ejection head according to claim 1. The liquid ejection head according to claim 1, wherein the convex portion further includes a third layer between the second layer and the substrate. 5. The liquid ejection head further includes an electrode pad for supplying electricity to the energy generating element, and the electrode pad is made of the same metal as the third layer. Liquid ejection head. 5. The liquid ejection head according to claim 4, wherein the third layer is made of Ir or has a multilayer structure in which the outermost layer in contact with the flow path forming member is made of Ir. A substrate, a flow path forming member in which an ejection port for ejecting liquid and a flow path for supplying liquid to the ejection port are formed, and an energy generating element configured to generate energy for ejecting the liquid. A method of manufacturing a liquid ejection head having the following steps:
The substrate has a convex portion protruding from the substrate side toward the flow path forming member,
The convex portion includes a second layer and a first layer in order from the substrate side,
A cross-sectional area of the second layer in a direction parallel to the substrate is smaller than a cross-sectional area of the first layer in a direction parallel to the substrate,
The manufacturing method includes:
a step (1) of forming the first layer and the second layer on the substrate;
a step (2) of patterning the first layer by anisotropic etching;
a step (3) of patterning the second layer by isotropic etching;
(4) forming the flow path forming member on the substrate so as to enter a space surrounded by the first layer of the convex portion and the substrate;
1. A method of manufacturing a liquid ejection head, comprising: in this order. In the step (1), the first layer is made of a material represented by the following general formula (1) Si _w O _x C _y N _z (w+x+y+z=100, 37≦w≦60, 30≦x≦53, 6 ≦y≦29, 4≦z≦9)...(1)
formed by
8. The method for manufacturing a liquid ejection head according to claim 7, wherein the second layer is formed of SiO or _SiO2 . The liquid ejection head further includes an electrode pad for supplying electricity to the energy generating element, and the manufacturing method includes:
In the step (2), anisotropically etching the first layer formed on the electrode pad,
9. The method for manufacturing a liquid ejection head according to claim 7, wherein in the step (3), the second layer formed on the electrode pad is isotropically etched. The liquid ejection head further includes an anti-cavitation film on the surface of the substrate, and the manufacturing method includes, prior to the step (1), simultaneously forming the electrode pad and the anti-cavitation film using the same material. The method for manufacturing a liquid ejection head according to claim 9, comprising the step of forming.

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